We all know that we’d be healthier, happier and sharper if we exercised regularly. But despite our best intentions, it rarely happens.

The federal government recommends getting at least two-and-a-half hours of exercise a week. To the average couch potato, though, that sounds like a Herculean task.

Now for the good news: a new study suggests that you don’t have to work out that much to gain health benefits. Even small amounts of physical activity — say, half the government’s recommendation — are enough to improve heart health.

The study was a meta-analysis of 33 previous studies examining the association between exercise and heart disease risk; nine of the studies estimated the quantity of physical activity people got. The researchers found that participants who got the recommended 150 minutes of physical activity per week had a 14% lower risk of heart disease than those who were sedentary.

Of course, more was better: people who managed 300 minutes of exercise per week had a 20% reduction in heart disease risk, compared with sedentary people. Beyond that, however, the relative benefits appeared to diminished; those who got a whopping 750 minutes per week had a 25% lower risk of heart disease than non-exercisers.

The researchers also found that even little bits of activity — just 75 minutes a week, which amounts to an easy 15-minute walk each weekday — offered significant benefit. People who eked out that much exercise still enjoyed a 14% lower heart risk than those who didn’t work out at all.

A while back, Jacob Sattelmair was working on a doctorate in epidemiology at the Harvard School of Public Health when he realized that there wasn’t a review spelling out just how much physical activity is needed to lower the risk of heart attacks and stroke.

The studies tended to look at the intensity of effort, not amount. So he and his colleagues combed 3,194 papers, and came up with nine that addressed the “how much?” question. They crunched the numbers in those studies to figure out what works.

The results should help motivate even the busiest of us to squeeze in at least a little bit more physical activity a day. And they could help encourage the sedentary to get started. “If you are doing nothing, do something,” Barry Franklin, a spokesman for the American Heart Association, told HealthDay. “And if you are doing something, say, walking 10 or 15 minutes, two to three times a week, do more.”

Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’sFacebook page and on Twitter at @TIME.